主要农作物转基因研究现状和展望

近15年来,大豆、水稻、玉米、小麦等主要农作物转基因研究取得了较大进展,几乎各种遗传转化方法在这些作物上都取得了成功,尤其是农杆菌介导法,不仅在难转化的双子叶作物大豆上取得了成功,而且在单子叶作物水稻、玉米、小麦上先后取得了突破。同时,将一些与重要性状改良有关的外源基因转入了主要农作物,包括抗虫、抗病、抗除草剂、抗逆、品质改良、发育调控、营养吸收等。转基因大豆、玉米、棉花、油菜在生产上得到了大面积种植,产生了极大的经济效益,2004年全球转基因作物的种植面积达到了8100万公顷。本文对大豆、玉米、水稻和小麦等主要农作物转基因研究历史和产业化现状进行了综述,并对主要农作物转基因研究中存在的问题进行了分析。     

甜菜夜蛾防控技术研究与示范——公益性行业(农业)科研专项“甜菜夜蛾防控技术研究与示范”研究进展

针对当前我国蔬菜生产中甜菜夜蛾Spodoptera exigua(Hübner)高抗药性、猖獗为害、防控困难的现状,项目组对甜菜夜蛾的发生规律、越冬与迁飞、抗药性、生物防治与综合防控等进行了系统的研究。明确了甜菜夜蛾在我国各地的发生规律及发生动态,从南到北发生时间呈楔形,而发生量总体东高西低,从南到北呈中部高南北低的马鞍形。阐述了甜菜夜蛾"无卵子发生-飞行拮抗"的迁飞特性,提出了接力棒式季节性南北往返迁飞模式,初步阐明了甜菜夜蛾在我国东部地区的迁飞路线与迁飞时间。提出并认证了甜菜夜蛾在我国的越冬区域。明确了全国各主要发生区甜菜夜蛾对10种杀虫剂的抗药性水平,探明了甜菜夜蛾对茚虫威、甲氨基阿维菌素苯甲酸盐的抗性风险、交互抗性、种群适合度、抗性遗传规律和抗性机理,提出了抗药性治理措施。分别在海南、湖南、湖北、上海、天津等地进行了甜菜夜蛾田间药效试验,筛选出环境友好型高效杀虫剂7种。掌握了马尼拉陡胸茧蜂、夜蛾黑卵蜂和淡足侧沟茧蜂人工大量繁殖技术,改进了甜菜夜蛾核型多角体病毒生产工艺,解决了寄生蜂和病毒规模化生产及田间释放关键技术,达到规模化生产的要求。改进优化了甜菜夜蛾性引诱剂配方、研发出新型诱捕装置,并投入生产应用。集成出4套农业生产轻简化实用技术,华南、华中、华北、华东地区根据当地发生特点制定了4套防控方案。在全国甜菜夜蛾主要发生区建立试验基地16个,核心示范基地29个,年示范面积总计约3800hm2,取得显著的经济、社会和生态效益。     

有色膜遮光对烤烟生长和光合特性及其初烤品质的影响

以自然光为对照,采用红色、白色、蓝色、黄色4种有色薄膜于2010~2011年从团棵期开始对大田烤烟进行遮光处理,研究不同光质对烤烟生长、光合特性及初烤品质指标的影响。结果显示:(1)红膜处理最大叶长宽比最小、叶面积最大,黄膜处理则相反。(2)红、蓝膜处理烟叶净光合速率、气孔导度、蒸腾速率明显高于自然光处理,白、黄膜处理略高于对照或与对照持平,且遮膜处理前期红膜高于蓝膜处理,后期蓝膜高于红膜处理。(3)红、蓝膜处理有利于提高倒5叶SPAD值,黄膜处理则相反。(4)红膜处理显著降低了中部叶蛋白质、总氮含量和氮碱比,提高了施木克值,并显著提高了上部叶可溶性糖含量和氮碱比,降低了施木克值;蓝膜处理显著提高了中部叶烟碱和多酚含量,降低了可溶性糖含量、施木克值及氮碱比,并显著提高了上部叶蛋白质、总氮、烟碱和多酚含量,降低了施木克值,提高了氮碱比;黄膜处理显著降低了中上部叶蛋白质、总氮、烟碱和多酚含量,提高了上部叶施木克值、降低了氮碱比。研究表明,红、蓝膜处理更利于烟叶发育和光合特性的提高,初烤烟叶化学成分更协调,利于优质烟叶的形成。     

鱼腥草等根茎类植物高效栽培新技术

通过采用"无纺土工布垫底、布上排放种茎、育苗基质覆盖"的方法,栽培野生根茎类植物。新技术优化了作物地下茎的生长环境,降低了田间杂草和地下害虫的危害,减少农田施药造成的环境污染,促进地下茎及植株快速生长,使其高产优质;同时,还大大减轻了工作强度、节约了工时,有效降低了生产成本。该技术主要包括:大田准备、种茎消毒、无纺土工布铺设、种茎排放、育苗基质覆盖、田间肥水管理等步骤。     

施蚯蚓粪对日光温室土壤及番茄产量与品质的影响

设施蔬菜化肥过量施用造成土壤劣化、土传病虫害发生严重,从而导致蔬菜产量和品质下降。蚯蚓粪在改善土壤环境和促进蔬菜生长、提高产量和品质方面具有良好的效果。本试验在日光温室采用等量撒施和沟施两种方式研究了增施蚯蚓粪对土壤养分、酶活性、微生物数量及番茄生长、产量和品质的影响。结果表明: 与不施蚯蚓粪的对照相比,撒施蚯蚓粪和沟施蚯蚓粪处理均改善了土壤环境,显著增加了土壤有机质和氮、磷、钾等养分含量;显著提高了蔗糖酶和过氧化氢酶活性,增加了土壤中细菌、放线菌数量,降低了真菌数量。沟施蚯蚓粪处理明显促进了植株地上部的生长,撒施效果不显著。蚯蚓粪处理明显增强了植株根系活力,提高了叶片的光合作用和叶绿素含量,促进了植株氮和钾含量的积累。撒施和沟施蚯蚓粪处理的番茄产量比对照分别提高了22.7%和32.6%。沟施处理果实中可溶性蛋白、可溶性糖、维生素C和可滴定酸含量分别提高了66.1%、11.0%、122.6%和29.9%,硝酸盐含量降低了65.7%,而撒施处理对番茄果实品质提升效果不明显。     

我国蓝藻水华的发生机理、危害及防控利用研究进展

近些年蓝藻水华的大规模爆发不仅危害了水产养殖业,而且严重影响了人类日常生活、供水、旅游业等。主要介绍了蓝藻水华爆发的内在因素（假空泡、类胡萝卜素、厚壁孢子、细胞壁等）及外在因素（营养物质、温度、微量元素、滤食性鱼类等）。阐述了蓝藻水华对生产、生态和生活造成的危害,归纳总结了蓝藻水华防控的化学、物理、生物等方法。最后描述了蓝藻水华的有效利用并提出其研究中存在的问题。     

我国绿色食品发展与现代农业建设关系的探讨

绿色食品发展与现代农业建设在存在较高契合度。近年来,我国绿色食品事业在国家现代农业推进的背景下,获得了持续健康发展。本文从发展总量、产品结构、贸易、品牌及国际化等方面分析了绿色食品发展状况,总结了绿色食品标准化、产业化以及品牌化发展模式,并从发展目标、实施路径、发展机制等角度详细论述了绿色食品与现代农业建设的关系,最后对绿色食品发展前景做出了判断并提出具体措施。     

龙眼树形对生长结果及机理影响初探

为了解决龙眼园的郁闭问题,提高龙眼的产量和品质,该文以桂香龙眼品种为材料,研究了扁开心形、开心形、自然圆头形三种不同树体结构对树体光照强度、叶片、根系、果实的影响。结果表明:扁开心形显著改善了树冠和果园通风透光环境,提高了叶绿素含量,增大了叶面积,提高了PSⅡ系统活性和开放程度,调节了光合机构的自我保护机制,改善了荧光参数,从而提高了果实品质;扁开心形、开心形、对照的单株产量分别是19.90、17.00、15.60 kg,单果重分别是10.24、10.07、7.64 g;扁开心形和开心形可食率比对照分别提高了4.20%、4.40%,可溶性固形物含量分别提高了12.16%、12.55%;扁开心形比开心形以及对照的表层根有所上浮,促进了果树的生殖生长,显著扩大了根系的分布深度,扩大了根系对营养物质以及水分的吸收。扁开心形是一种高光效的树形,应在生产上加以推广。     

绿色基础设施研究进展

综述了绿色基础设施的起源发展,总结了推动其概念形成的发展脉络,分别是人居环境视角、生态保护视角和绿色技术视角。提出了绿色基础设施在空间、功能、要素上的内涵,阐述了它与生态系统服务的外延关系。通过文献研究,综述了绿色基础设施在气候变化、人体健康、空气质量、雨洪管理、公众认知和社区参与、评价研究等领域的国际研究进展。结合我国绿色基础设施的研究现状和问题进行评述,并对未来发展提出展望。     

菊芋悬浮细胞对盐胁迫的生理响应

为探讨菊芋（Helianthus tuberosus）悬浮培养细胞对盐胁迫的生理响应,在0、50、100、150、200 mmol·L^-1NaCl处理下测定了细胞的生物量、相对细胞活力、抗氧化酶活性以及过氧化氢、丙二醛、脯氨酸、可溶性糖、可溶性蛋白质的含量,测定了总酚含量并鉴别、定量分析了14种酚类化合物。结果表明：盐胁迫显著减弱了菊芋悬浮细胞的活力,抑制了细胞的增长,200 mmol·L^-1NaCl处理下细胞生长基本上停止。盐胁迫诱发了细胞氧化胁迫,丙二醛含量显著增加,抗坏血酸过氧化物酶、过氧化物酶活性以及总酚含量、部分酚类化合物含量均随NaCl浓度升高而增加,酚类物质和抗氧化酶系统共同参与了应对氧化胁迫的抗氧化作用。脯氨酸在菊芋悬浮细胞应对NaCl渗透胁迫的渗透调节作用中扮演了重要的角色,而可溶性糖发挥的作用不大。     

Bioavailability of synthetic and biosynthetic deuterated lycopene in humans

Current knowledge of the bioavailability of lycopene in humans is limited due to the inability to distinguish newly administered lycopene from the body reserves of lycopene. A quantitative method to assess the absorption and relative bioavailability of newly absorbed synthetic or natural lycopene was developed using two deuterated lycopene sources, in conjunction with an advanced LC/APCI-MS (liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry) to analyze newly absorbed lycopene in blood samples of study subjects. Two subjects (1 male and 1 female) consumed hydroponically grown tomatoes containing deuterium-enriched lycopene (80-84 g wet weight tomato containing 16.3 and 17.4 micromol lycopene, respectively) and two subjects (1 male, and 1 female) consumed 11 micromol synthetic (2)H(10) lycopene in 6 g of corn oil. Tomatoes were steamed and pureed. The doses were given together with a liquid formulated drink with 25% energy from fat. Our results showed that up to 34 days after taking an oral (2)H(10) lycopene dose (synthetic or from tomato) with a liquid formula drink, the area under the curve of the average serum percent enrichment response of synthetic lycopene reached 33.9 (+/-1.7) nmol-day/micromol lycopene in the dose, whereas that of lycopene from the tomato dose was 11.8 (+/-0.3) nmol-day/mumol lycopene in the dose. Our study provides evidence that the absorption of physiological levels of lycopene in intrinsically labeled tomatoes can be studied in humans. From these preliminary investigations, we find that the bioavailability of synthetic lycopene in oil appears to be about three times higher than that of lycopene from steamed and pureed tomatoes.     

Real Time Detection of Reactions Between Radicals of Lycopene and Tocopherol Homologues

Laser flash photolysis of lycopene in homogeneous chloroform solution together with tocopherol homolopes results in rapid formation of the lycopene radical cation and slower formation of tocopheroxyl radicals. Time-resolved detection by absorption spectroscopy of decay of the lycopene radical cation, of formation of the tocopheroxyl radicals, and of bleaching of lycopene has shown that a-tocopherol is able to reduce the lycopene radical cation and thereby partially regenerate lycopene on a ms timescale. In contrast, lycopene is able to reduce the δ-tocopheroxyl radical, whereas an equilibrium exists between the lycopene radical cation and β- or γ-tocopherol. The relative stability of these antioxidant radicals is hence: a-tocopheroxyl > lycopene radical cation ≈ β-tocopheroxyl - γ-tocopheroxyl > S-toco-pheroxyl.     

A review of animal model studies of tomato carotenoids,lycopene, and cancer chemoprevention

There are relatively few reports on the cancer chemopreventive effects of lycopene or tomato carotenoids in animal models. The majority, but not all, of these studies indicate a protective effect. Inhibitory effects were reported in two studies using aberrant crypt foci, an intermediate lesion leading to colon cancer, as an end point and in two mammary tumor studies, one using the dimethylbenz(a)anthracene model, and the other the spontaneous mouse model. Inhibitory effects were also reported in mouse lung and rat hepatocarcinoma and bladder cancer models. However, a report from the author's laboratory found no effect in the N-nitrosomethylurea-induced mammary tumor model when crystalline lycopene or a lycopene-rich tomato carotenoid oleoresin was administered in the diet. Unfortunately, because of differences in routes of administration (gavage, intraperitoneal injection, intra-rectal instillation, drinking water, and diet supplementation), species and strain differences, form of lycopene (pure crystalline, beadlet, mixed carotenoid suspension), varying diets (grain-based, casein based) and dose ranges (0.5-500 ppm), no two studies are comparable. It is clear that the majority of ingested lycopene is excreted in the feces and that 1000-fold more lycopene is absorbed and stored in the liver than accumulates in other target organs. Nonetheless, physiologically significant (nanogram) levels of lycopene are assimilated by key organs such as breast, prostate, lung, and colon, and there is a rough dose-response relationship between lycopene intake and blood levels. Pure lycopene was absorbed less efficiently than the lycopene-rich tomato carotenoid oleoresin and blood levels of lycopene in rats fed a grain-based diet were consistently lower than those in rats fed lycopene in a casein-based diet. The latter suggests that the matrix in which lycopene is incorporated is an important determinant of lycopene uptake. A number of issues remain to be resolved before any definitive conclusions can be drawn concerning the anticancer effects of lycopene. These include the following: the optimal dose and form of lycopene, interactions among lycopene and other carotenoids and fat soluble vitamins such as vitamin E and D, the role of dietary fat in regulating lycopene uptake and disposition, organ and tissue specificity, and the problem of extrapolation from rodent models to human populations.     

Effects of lycopene-beadlet or tomato-powder feeding on carbon tetrachloride-induced hepatotoxicty in rats.

The carotenoid lycopene has been touted as possessing various antioxidant properties, but there are no demonstrations that lycopene inhibits tissue injury due to acute oxidant stress. Thus, the present study examined the effects of intake of lycopene or tomato extract, a rich source of lycopene, on acute liver injury caused by the oxidant carbon tetrachloride (CCl4). Feeding with tomato extract (10% tomato powder), but not with lycopene (0.25% lycopene beadlets), partially inhibited CCl4-induced hepatic injury based on the serum activities of sorbitol dehydrogenase and aspartate aminotransferase. No effect was seen for either lycopene or tomato extract on serum beta-glucuronidase activity, a marker of lysosomal injury. We concluded that tomato extract, but not lycopene, partially protected against acute liver injury due to chemically-induced oxidant stress.     

高产番茄红素链霉菌选育及摇瓶发酵研究

番茄红素的抗氧化能力目前在类胡萝卜素中最强,是近年来国际上功能食品成分研究的热点。在国内首次利用龟裂链霉菌（Streptomyces rimosus）发酵生产番茄红素,建立了分光光度计法和HPLC法等番茄红素测定方法;以一株龟裂链霉菌Fc作为出发菌株,进行紫外诱变,筛选到一株突变高产菌株Fc’,其番茄红素产量较出发菌株提高2.5倍;通过摇瓶发酵实验优化培养条件,使菌株Fc’的番茄红素产量达到230 mg/L,并且在不添加任何阻断剂的情况下,利用链霉菌发酵可获得纯度较高的番茄红素。该结果为今后利用链霉菌工业化生产番茄红素奠定了良好基础。     

Lycopene, tomatoes, and coronary heart disease

Tomato and its major antioxidant component lycopene have recently been focused as important antioxidant nutrients because of their ability to reduce reactive oxygen species and to provide health benefits. Most of the studies were undertaken to determine the usefulness of lycopene against cancer and cardiovascular diseases. Epidemiological studies, however, yielded conflicting results. This study was undertaken to compare cardioprotective abilities of tomato juice and lycopene. Rats were gavaged either tomato juice or lycopene for 3 weeks. At the end of 3 weeks, isolated hearts were subjected to 30 min ischemia followed by 2 h of reperfusion. Both tomato juice and lycopene reduced the extent of lipid peroxidation; but only tomato juice, but not lycopene, improved post-ischemic ventricular function, and reduced myocardial infarct size and cardiomyocyte apoptosis. The results indicated for the first time that tomato juice, but not lycopene, possesses cardioprotective ability.     

Lycopene in tomatoes: chemical and physical properties affected by food processing

Lycopene is the pigment principally responsible for the characteristic deep-red color of ripe tomato fruits and tomato products. It has attracted attention due to its biological and physicochemical properties, especially related to its effects as a natural antioxidant. Although it has no provitamin A activity, lycopene does exhibit a physical quenching rate constant with singlet oxygen almost twice as high as that of beta-carotene. This makes its presence in the diet of considerable interest. Increasing clinical evidence supports the role of lycopene as a micronutrient with important health benefits, because it appears to provide protection against a broad range of epithelial cancers. Tomatoes and related tomato products are the major source of lycopene compounds, and are also considered an important source of carotenoids in the human diet. Undesirable degradation of lycopene not only affects the sensory quality of the final products, but also the health benefit of tomato-based foods for the human body. Lycopene in fresh tomato fruits occurs essentially in the all-trans configuration. The main causes of tomato lycopene degradation during processing are isomerization and oxidation. Isomerization converts all-trans isomers to cis-isomers due to additional energy input and results in an unstable, energy-rich station. Determination of the degree of lycopene isomerization during processing would provide a measure of the potential health benefits of tomato-based foods. Thermal processing (bleaching, retorting, and freezing processes) generally cause some loss of lycopene in tomato-based foods. Heat induces isomerization of the all-trans to cis forms. The cis-isomers increase with temperature and processing time. In general, dehydrated and powdered tomatoes have poor lycopene stability unless carefully processed and promptly placed in a hermetically sealed and inert atmosphere for storage. A significant increase in the cis-isomers with a simultaneous decrease in the all-trans isomers can be observed in the dehydrated tomato samples using the different dehydration methods. Frozen foods and heat-sterilized foods exhibit excellent lycopene stability throughout their normal temperature storage shelf life. Lycopene bioavailability (absorption) can be influenced by many factors. The bioavailability of cis-isomers in food is higher than that of all-trans isomers. Lycopene bioavailability in processed tomato products is higher than in unprocessed fresh tomatoes. The composition and structure of the food also have an impact on the bioavailability of lycopene and may affect the release of lycopene from the tomato tissue matrix. Food processing may improve lycopene bioavailability by breaking down cell walls, which weakens the bonding forces between lycopene and tissue matrix, thus making lycopene more accessible and enhancing the cis-isomerization. More information on lycopene bioavailability, however, is needed. The pharmacokinetic properties of lycopene remain particularly poorly understood. Further research on the bioavalability, pharmacology, biochemistry, and physiology must be done to reveal the mechanism of lycopene in human diet, and the in vivo metabolism of lycopene. Consumer demand for healthy food products provides an opportunity to develop lycopene-rich food as new functional foods, as well as food-grade and pharmaceutical-grade lycopene as new nutraceutical products. An industrial scale, environmentally friendly lycopene extraction and purification procedure with minimal loss of bioactivities is highly desirable for the foods, feed, cosmetic, and pharmaceutical industries. High-quality lycopene products that meet food safety regulations will offer potential benefits to the food industry.     

Effects of lycopene and tomato paste extracts on DNA and lipid oxidation in LNCaP human prostate cancer cells

Animal and epidemiological studies point to a cancer preventive/therapeutic role for tomato products and its antioxidant, lycopene. It is hypothesized that lycopene will behave as an antioxidant at low concentrations and as a prooxidant at high concentrations in LNCaP human prostate cancer cell culture systems. We characterized the antioxidant, and prooxidant effects of a hexane extract of tomato paste (TP) and water solubilized lycopene at different concentrations using a prostate cancer cell line. Placebo (5% triglyceride, Roche Inc.) was used as a control. After 6, 24 hr and 48 hr incubation, LNCaP cells were harvested and used for each measurement. Cellular proliferation was determined using the MTT colorimetric assay. Lycopene and TP hexane extract inhibited cell growth in a dose-dependent (0.1-50 microM lycopene) manner and growth inhibition was 55% and 35% at 1 microM lycopene and TP hexane extract, respectively after 48 hr incubation. The levels of 8-hydroxydeoxyguanosine/deoxyguanosine (an oxidative DNA damage product) was significantly increased starting at 5 microM lycopene from both TP hexane extract and pure lycopene after 24 and 48 hr incubation with no protection at the lower concentrations. Malondialdehyde formation (a lipid peroxidation product measured by HPLC separation of the MDA-TBA adduct) was significantly reduced at low concentrations (0.1-1 microM) of lycopene in all treatments. Clinically relevant concentrations of lycopene and the tomato fraction containing lycopene significantly reduced LNCaP cancer cell survival which can only be partially explained by increased DNA damage at high lycopene concentrations (> 5 microM). Low concentrations of lycopene acted as a lipid antioxidant but did not protect DNA.     

Lycopene,tomatoes, and coronary heart disease

Tomato and its major antioxidant component lycopene have recently been focused as important antioxidant nutrients because of their ability to reduce reactive oxygen species and to provide health benefits. Most of the studies were undertaken to determine the usefulness of lycopene against cancer and cardiovascular diseases. Epidemiological studies, however, yielded conflicting results. This study was undertaken to compare cardioprotective abilities of tomato juice and lycopene. Rats were gavaged either tomato juice or lycopene for 3 weeks. At the end of 3 weeks, isolated hearts were subjected to 30?min ischemia followed by 2?h of reperfusion. Both tomato juice and lycopene reduced the extent of lipid peroxidation; but only tomato juice, but not lycopene, improved post-ischemic ventricular function, and reduced myocardial infarct size and cardiomyocyte apoptosis. The results indicated for the first time that tomato juice, but not lycopene, possesses cardioprotective ability.